Japanese macaque description

Known as the snow monkey, the Japanese macaque (Macaca fuscata) is the most northerly occurring non-human primate (4). In general, macaques are strong-limbed, medium-sized monkeys with stout bodies (5). This species has long, dense fur which is brown to grey in colour (2)(5). The thick fur contrasts with the naked skin of the face and rump, which is red in adult Japanese macaques (2). It has long whiskers, a beard and a relatively short tail (2)(5). The male Japanese macaque is larger than the female (2).

The Japanese macaque utilises a variety of vocalisations, including shrill alarm barks, squawks of surprise and growls of aggression (5).

Related species

Japanese macaque biology

The Japanese macaque is diurnal, variably spending the daytime foraging, travelling, socially interacting and resting. It is an unfussy eater and its diet varies with habitat and season (7). Typically, it feeds on leaves, fruit, berries, seeds, small animals, insects and even fungi (1)(7).

As with all species of macaque, the Japanese macaque lives in large social groups known as ‘troops’ (8). Group size can vary greatly, with an average troop containing around 41 individuals (7). Troops that are provisioned with extra food have been known to reach as many as 700 individuals (5). Within the troop, the females are maternally related, while male Japanese macaques transfer between troops (9). There is a strict dominance hierarchy, with lower ranking individuals having less access to resources such as food (10). A young female macaque inherits its mother’s rank, and is also dominant to its younger siblings (11).

In the Yakushima Island subspecies (Macaca fuscata yakui), the breeding season begins in September and lasts until February (9). The male competes for access to receptive females, with higher ranking males gaining more mating opportunities (9). The female is usually reproductively active between the ages of 6 and 18 years of age, and will mate with an average of 10 males during the breeding season, continuing to mate even after conception (4)(5)(9). The gestation period for the Japanese macaque is around 173 days, after which a single infant is usually born, though twins are not unheard of (5)(12).

With its thick coat, the Japanese macaque can survive winter temperatures of -15 degrees Celsius. However, it is probably most well known for its habit of sitting in natural hot springs in order to escape the winter extremes (4)(7). Japanese macaques are also thought to display ‘culture’, where a learned behaviour is passed through the troop (11). The most famous example of this is where a young female in a provisioned troop began washing potatoes and wheat in sea water. This behaviour was transmitted to other members of the troop and has since been passed on to subsequent generations (11).

Japanese macaque range

The Japanese macaque is native to Japan, where it is found on three of the four main islands: Honshu, Shikoku and Kyushu (1)(6). It also occupies several smaller islands, with the most southerly population occurring on Yakushima Island (Macaca fuscata yakui) (6). Its northern range extends to the Shimokita peninsula of Honshu (6).

There is also an introduced population of Japanese macaques in Texas, North America (7).

Japanese macaque threats

Although not considered to be globally threatened, the Japanese macaque still faces a number of threats. The clearing of natural forest for the planting of valuable Japanese cedar (Cryptomeria japonica) and for building highways has reduced the amount of available habitat for this species (6).

Historically, the Japanese macaque has been hunted for food and medicinal use (6). Although hunting was forbidden in 1947, some poaching has continued. It is also killed, legally, as a pest when raiding crop fields, with some 10,000 individuals killed each year (1)(6). The provisioning of troops with extra food may be in part to blame for crop raiding behaviour, increasing population numbers in certain areas beyond the natural capacity (6).

Japanese macaque conservation

The Japanese macaque has officially been protected from hunting since 1947 and is also listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), which means that trade in this species should be carefully monitored (1)(3). It occurs in 16 national parks, although there are concerns that the level of tourism in these areas may be detrimental to Japanese macaque populations (6).

Future recommendations for the conservation of the Japanese macaque include establishing reservations where tourism is prohibited, providing better protection of crops so that raiding monkeys will not have to be killed, supervising provisioning of food and establishing breeding colonies for the supply of laboratory monkeys (6).

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